System Operation
Supplemental Restraint System
System Operation
System Diagram - Supplemental Restraint System (SRS)
Network Message Chart - Supplemental Restraint System (SRS)
Module Network Input Messages - RCM (Restraints Control Module)
System Diagram - Occupant Classification System (OCS)
Network Message Chart - Occupant Classification System (OCS)
Module Network Input Messages
Supplemental Restraint System
The SRS (Supplemental Restraint System) is controlled by the RCM (Restraints Control Module), which continually monitors various inputs. When these inputs indicate a frontal or side crash, the RCM (Restraints Control Module) may deploy some components, based upon the severity of the crash and the sensor inputs. REFER to System Diagram - Supplemental Restraint System (SRS) to view the SRS (Supplemental Restraint System) inputs and outputs.
Although some deployable devices may not have activated for all occupants during a crash, it does not mean that something is wrong with the SRS (Supplemental Restraint System).
The RCM (Restraints Control Module) performs a self-test of the complete SRS (Supplemental Restraint System) during each startup. In addition to the self-test at start up, the RCM (Restraints Control Module) continuously monitors all of its SRS (Supplemental Restraint System) components and circuitry for correct operation.
Air Bag Module Second Stage Deployment Check
The driver and passenger front air bags each have 2 deployment stages. After an air bag module deployment, it is possible that stage 1 has deployed and stage 2 has not. If a front air bag module has deployed, the front air bag module must be remotely deployed using the appropriate air bag disposal procedure to make sure both stages have been deployed. For information on driver air bag module and/or passenger air bag module remote deployment, REFER to Pyrotechnic Device Disposal .
Air Bag Warning Indicator
The air bag warning indicator:
- proves out by lighting for 6 seconds and then turning off.
- flashes and/or illuminates based on the message that the IPC (Instrument Panel Cluster) receives from the RCM (Restraints Control Module).
- illuminates if the IPC (Instrument Panel Cluster) does not receive a message from the RCM (Restraints Control Module).
When the ignition is turned ON during normal operation, the IPC (Instrument Panel Cluster) illuminates the air bag warning indicator continuously for 6 seconds. If the SRS (Supplemental Restraint System) is free of faults, the air bag warning indicator turns off and remains off. If a SRS (Supplemental Restraint System) fault exists, the air bag warning indicator illuminates and remains illuminated for the rest of the ignition cycle. The RCM (Restraints Control Module) communicates with the IPC (Instrument Panel Cluster) via the HS-CAN (High Speed Controller Area Network) and MS-CAN (Medium Speed Controller Area Network). The IPC (Instrument Panel Cluster) illuminates the air bag warning indicator based on messaging from the RCM (Restraints Control Module) (through the BCM (Body Control Module), which acts as a gateway module). The IPC (Instrument Panel Cluster) also illuminates the air bag warning indicator if there is no communication between the RCM (Restraints Control Module) and IPC (Instrument Panel Cluster).
Event Notification Signal
The purpose of the event notification feature is to provide other vehicle subsystems with information pertaining to restraint system deployment or fuel cutoff status. When an impact occurs which exceeds a pre-determined threshold, the RCM (Restraints Control Module) sends a signal on a dedicated circuit to the BCM (Body Control Module). The BCM (Body Control Module) sends a signal on a second hardwired circuit to the PCM (Powertrain Control Module), which initiates fuel cut-off and disables the fuel system.
OCS (Occupant Classification System)
The OCS (Occupant Classification System) classifies the size of the front passenger seat occupant and provides this information to the RCM (Restraints Control Module). The RCM (Restraints Control Module) uses this information (and other inputs) in determining the deployment strategy of the passenger air bag, adaptive load limiter, passenger seat side air bag and pretensioner.
Pressure is applied to the OCS (Occupant Classification System) bladder when weight of any occupant or object in the front passenger seat is present. The pressure is then transferred through a tube and sensed by the OCS (Occupant Classification System) pressure sensor within the OCSM (Occupant Classification System Module). The OCSM (Occupant Classification System Module) sends information concerning the weight of any occupant or object on the front passenger seat to the RCM (Restraints Control Module) via the HS-CAN (High Speed Controller Area Network). The RCM (Restraints Control Module) uses this information when determining if the passenger air bag module needs to be deployed in the event of a crash.
The OCS (Occupant Classification System) is also used for operation of the passenger Belt-Minder(R). For additional information on the passenger Belt-Minder(R) feature, REFER to Belt-Minder(R) . To deactivate or reactivate the passenger Belt-Minder(R) feature, REFER to Belt-Minder Deactivating and Activating Testing and Inspection or the Owner's Literature.
PAD (Passenger Air Bag Deactivation) Indicator
The RCM (Restraints Control Module) controls the state of the PAD (Passenger Air Bag Deactivation) indicator through a direct, hardwired connection, based on information provided by the OCS (Occupant Classification System). The PAD (Passenger Air Bag Deactivation) indicator illuminates to indicate the passenger air bag module is disabled. An exception to this is when the front passenger seat is determined to be empty and indication of a deactivated passenger air bag module is not necessary. In all other cases, the PAD (Passenger Air Bag Deactivation) indicator is off when the passenger air bag module is enabled.
The RCM (Restraints Control Module) briefly activates the PAD (Passenger Air Bag Deactivation) indicator to prove out the indicator function and verify proper functional operation of the PAD (Passenger Air Bag Deactivation) indicator to the front occupants.
The following table indicates the passenger air bag and PAD (Passenger Air Bag Deactivation) indicator status based on the size of the front passenger occupant.
Secondary Air Bag Warning
A secondary air bag warning message is displayed and controlled by the IPC (Instrument Panel Cluster). If the RCM (Restraints Control Module) detects an SRS (Supplemental Restraint System) fault, the RCM (Restraints Control Module) sends a message to the BCM (Body Control Module), which gateways the message and sends it to the IPC (Instrument Panel Cluster), which then illuminates the air bag warning indicator. If the IPC (Instrument Panel Cluster) detects a fault with the air bag warning indicator, a DTC (Diagnostic Trouble Code) is stored in memory in the IPC (Instrument Panel Cluster) and a warning message is displayed in the message center to indicate that a SRS (Supplemental Restraint System) fault is present.
SOS Post-Crash Alert System(TM)
The SOS Post-Crash Alert System(TM) is controlled by the BCM (Body Control Module), but initiated by the RCM (Restraints Control Module).
When a deployment event occurs, the RCM (Restraints Control Module) sends a message on the HS-CAN (High Speed Controller Area Network) to the BCM (Body Control Module). The BCM (Body Control Module) flashes the turn signal lamps and sounds the horn until it is turned off. The BCM (Body Control Module) also unlocks the doors. For additional information about the SOS Post-Crash Alert System(TM) , REFER to Post Crash Alert Function .
In addition to the SOS Post-Crash Alert System(TM) functions, the BCM (Body Control Module) turns the interior lights on and turns the windshield wipers off if the vehicle is not moving after a crash has occurred.